Electrochemical Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy: Correlating Structural Information and Adsorption Processes of Pyridine at the Au(hkl) Single Crystal/Solution Interface

Abstract

Electrochemical methods are combined with shell-isolated nanoparticle-enhanced Raman spectroscopy (EC-SHINERS) for a comprehensive study of pyridine adsorption on Au(111), Au(100) and Au(110) single crystal electrode surfaces. The effects of crystallographic orientation, pyridine concentration, and applied potential are elucidated, and the formation of a second pyridine adlayer on Au(111) is observed spectroscopically for the first time. Electrochemical and SHINERS results correlate extremely well throughout this study, and we demonstrate the potential of EC-SHINERS for thorough characterization of processes occurring on single crystal surfaces. Our method is expected to open up many new possibilities in surface science, electrochemistry and catalysis. Analytical figures of merit are discussed.

Advances in surface-enhanced vibrational spectroscopy at electrochemical interfaces

“…The process was found to be highly surface structure sensitive on Au(hkl) as a result of the different surface charge characteristics of the crystallographic faces [100]. Furthermore, at sufficiently high pyridine concentrations, new features appeared in the SHINERS spectra that were attributed to the adsorption of a second adlayer of pyridine ( Figure 5(e)) [100]. Measurements have also been extended to single crystal SHINERS measurements in ionic liquids [104].…”

“…Procedures to synthesise SHINs are now well-documented [85], typical particles comprising a 55-120 nm spherical gold or silver core [82,86,87] [92], graphene [93,94] and other carbon materials [95,96]. Example core-shell particles are depicted in Figure 5 The substrate generality of SHINERS has greatly benefitted electrochemical Raman spectroscopy and an impressive range of native electrode substrates have been investigated including Ag [97,98], Au [99][100][101][102][103][104], Pt [99,102], Pd [102], Rh [105], Ni alloys [106,107], Cu [108] and glassy carbon (GC) [102]. Moreover, SHINERS enables the detailed investigation of single crystal electrodes, which are of tremendous interest as model systems from a surface science perspective, allowing the effect of surface atomic structure on behaviour and reactivity to be systematically investigated [109].…”

“…Moreover, SHINERS enables the detailed investigation of single crystal electrodes, which are of tremendous interest as model systems from a surface science perspective, allowing the effect of surface atomic structure on behaviour and reactivity to be systematically investigated [109]. For example, various researchers have investigated pyridine adsorption at single crystal Au and Pt surfaces using EC-SHINERS [100,101,110]. The process was found to be highly surface structure sensitive on Au(hkl) as a result of the different surface charge characteristics of the crystallographic faces [100].…”

“…For example, various researchers have investigated pyridine adsorption at single crystal Au and Pt surfaces using EC-SHINERS [100,101,110]. The process was found to be highly surface structure sensitive on Au(hkl) as a result of the different surface charge characteristics of the crystallographic faces [100]. Furthermore, at sufficiently high pyridine concentrations, new features appeared in the SHINERS spectra that were attributed to the adsorption of a second adlayer of pyridine ( Figure 5(e)) [100].…”

Large scale synthesis of pinhole‐free shell‐isolated nanoparticles (SHINs) using improved atomic layer deposition (ALD) method for practical applications

“…The rapid development of SHINERS technique offsets the longstanding limitations of SERS such as substrate and morphology generality to a certain extent. Therefore, SHINERS has been widely accepted by different fields such as surface science, [14,15] analytical science, [16] electrochemistry, [17][18][19][20][21][22] material science, [23][24][25] life science [26,27] and other fields. [28][29][30][31] Chemical method is the conventional protocol to prepare metal nanoparticles with thin layer of inert dielectric shell; the shell thickness can be adjusted between 1 and 5 nm with controlled reaction time.…”